This is a competitive supplement to an existing National Alcohol Research Center grant, to establish a major component of that center dealing with behavioral links between alcohol and AIDS. The proposed research focuses on alcohol's involvement in behaviors that increase the risk of contracting AIDS, in particular through sexual risk-taking. Both survey and experimental methodologies are employed. Three main aims guide the proposed research program: (1) To develop estimates of the incidence and prevalence of sexual risk-taking and drinking in several populations. (2) To examine psychosocial mediators or theoretical, models for the connection between drinking and sexual risk-taking--including examination of the roles of beliefs and expectations about alcohol's effects, normative perceptions of intoxicated behavior, sexual attitudes, perceptions of AIDS risk, and more generalized risk-taking tendencies. (3) To examine process and change in the interrelationships among drinking, drug use, and sexual behavior. A five-year series of interrelated substudies is proposed, comprising: (a) A national survey (in conjunction with a scheduled 1989 national survey of drinking practices) to explore drinking and sexual behavior, perceptions of and attitudes towards AIDS, and including an oversampling of youths and young adults in order to study this specially at-risk subgroup. (b) A longitudinal follow-up of youth and young adults in order to chart individual and historical change in drinking and sexual practices. (c) Studies of national samples of Black and Hispanic adults, including a longitudinal link to ARG's 1984 national survey. (d) Studies in the general population and of the criminal justice population of Contra Costa County, California, in the context of a Community Epidemiology Laboratory. (e) And, finally, a series of social-psychological experimental studies designed to offer convergent evidence on alcohol's role in sexual risk-taking.